Targeted UHPLC-ESI-MS/MS Analysis of Selected Neurotransmitters, Tryptophan and Its Metabolite Kynurenine in Tau Transgenic Rat Brain Tissue: A Pivotal Study

Neurotransmitters (NT) are widely distributed in the central nervous system. These molecules are important for many physiological processes and the function of the immune system. Imbalance of NT are linked to numerous neurological disorders and diseases, including tauopathies. Here, a targeted approach based on on-line combination of ultra-high performance liquid chromatography with tandem mass spectrometry was validated and applied to the quantitative analysis of nine NT (acetylcholine, choline, aspartic acid, asparagine, glutamic acid, glutamine, pyroglutamate, γ-aminobutyric acid, N-acetyl-L-aspartic acid), tryptophan and its metabolite kynurenine in brain tissue samples of a rat model for tauopathy. The applied analytical method was characterized by excellent validation parameters for all analytes, such as limits of detection in the range of 0.01–1.70 µg/mL, regression coefficients of the calibration curves ≥ 0.9946, intra-day and inter-day precision expressed as coefficient of variation in the range of 0.6–11.9% and 0.6–14.4%, and accuracy in the range of 87.6–107.1% and 87.2–119.6%. Our analytical approach led to the identification of increased levels of choline and γ-aminobutyric acid in pons, and elevated concentration levels of pyroglutamate in medulla oblongata. These findings indicate that NT could play a valuable role in the study and clarification of neuroinflammation and neurodegenerative diseases.

Simultaneous Rp-Hplc Method For Determination Of Betamethasone Dipropionate And Tolnaftate In Combined Semisolid Formulation

A new RP-HPLC method was developed for selective and simultaneous determination of betamethasone dipropionate and tolnaftate in combined semisolid formulation containing other components. Further, the proposed method was validated for linearity, precision (system precision, method precision, intermediate or inter-day precision), accuracy, stability in analytical solution, robustness or system suitability and ruggedness. The developed method exhibited the best results in terms of the aforesaid validation parameters. The other components and additives did not interfere in their determinations. The method was found to be selective, simple, economical, accurate, reproducible, rapid and reliable for routine estimation purpose of these drugs in combined semisolid formulations.

Simultaneous Determination of Caffeine and Paracetamol in Commercial Formulations Using Greener Normal-Phase and Reversed-Phase HPTLC Methods: A Contrast of Validation Parameters

There has been no assessment of the greenness of the described analytical techniques for the simultaneous determination (SMD) of caffeine and paracetamol. As a result, in comparison to the greener normal-phase high-performance thin-layer chromatography (HPTLC) technique, this research was conducted to develop a rapid, sensitive, and greener reversed-phase HPTLC approach for the SMD of caffeine and paracetamol in commercial formulations. The greenness of both techniques was calculated using the AGREE method. For the SMD of caffeine and paracetamol, the greener normal-phase and reversed-phase HPTLC methods were linear in the 50–500 ng/band and 25–800 ng/band ranges, respectively. For the SMD of caffeine and paracetamol, the greener reversed-phase HPTLC approach was more sensitive, accurate, precise, and robust than the greener normal-phase HPTLC technique. For the SMD of caffeine paracetamol in commercial PANEXT and SAFEXT tablets, the greener reversed-phase HPTLC technique was superior to the greener normal-phase HPTLC approach. The AGREE scores for the greener normal-phase and reversed-phase HPTLC approaches were estimated as 0.81 and 0.83, respectively, indicated excellent greenness profiles for both analytical approaches. The greener reversed-phase HPTLC approach is judged superior to the greener normal-phase HPTLC approach based on numerous validation parameters and pharmaceutical assays.

In-silico activity prediction, structure-based drug design, molecular docking and pharmacokinetic studies of selected quinazoline derivatives for their antiproliferative activity against triple negative breast cancer (MDA-MB231) cell line

Background Cancer is a major health threat especially in unindustrialized nations. It surpasses coronary diseases and takes the number one killer position as a result of different global wide influences. Among many breast cancer substrates, triple-negative breast cancer (TNBC) is particularly devastating because it rapidly metastasize to other parts of the body, with a high risk of earlier recession and mortality. Result In this research work, four (4) quantitative structure activity relationship (QSAR) models were developed using a series of quinazoline derivatives with activities against triple negative breast cancer cell line (MDA-MB231), model 1 was selected due to its statistical fitness with the following validation parameters: R2 = 0.875, Q2 = 0.837, R2 − Q2 = 0.038, Next test set = 5, and R2ext = 0.655. Molecular docking studies was performed for the quinazoline series as well as the reference drug (Gefitinib) and the active site of the epidermal growth factor receptor (EGFR) (pdb id = 3ug2). Eight compounds (6, 10, 13, 16, 17, 18, 19 and 20) were observed to have better docking score docking scores relative to Gefitinib. Compound number nineteen from the training set (pred pIC50 = 5.67, Residual = − 0.04 and MolDock score = − 123.238) was identified as the best compound since it has the best Moldock score and was excellently predicted by the selected model with least residual value, Hence was adopted as template for the design of Ten (10) new novel compounds with better activities and better docking scores. The inhibitive activities of the designed compounds were predicted by the selected model and most of them possess an improved activity relative to the template compound (19). The designed compounds were also redocked on to active pocket of the EGFR receptor and it was observed that they displayed better docking scores compared to the Template and the reference drug (Gefitinib) utilized in the design. Furthermore, the designed compounds were subjected to ADMET and drug-likeness studies using SWISSADME and pkCSM online web tools and they were observed to be pharmacologically active, easily synthesized and do not violate the Lipinski’s rule of five. Conclusion Hence, the designed compounds can be employed as inhibitors of MDA-MB231 cell line after passing through in vivo and in vitro evaluation.

Review of characteristics and analytical methods for determination of indomethacin

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the first choice of treatment for rheumatic disorders and other degenerative inflammatory diseases. One of them, indomethacin (INDO), is highlighted in this study. With its analgesic, antipyretic, and anti-inflammatory properties, it is one of the most powerful drugs used in various clinical trials and therapies related to the mechanism of blocking prostaglandin synthesis, thus reducing and eliminating many inflammatory conditions in patients. To ensure the efficacy and safety of this drug in pharmaceutical and clinical use, precise product quality control is required. Such control is performed with routine pharmaceutical analysis using various chemical methods by which INDO is identified as a separate active ingredient in the multicomponent system of a complete pharmaceutical form. In addition, the determination of INDO is important in clinical practice, where its concentration is determined in different biological samples, ensuring better monitoring of a particular therapy. The most commonly used methods for the determination of INDO are high-performance liquid chromatography (37% of developed methods), voltammetry (16% of developed methods), and UV spectroscopy (11% of developed methods). However, each of these methods must provide precise validation parameters. A combination of analytical methods can lead to more precise results and safer application in practice.

Synthesis of Cyanuric Chloride based Chiral Reagent for RP-HPLC Enantioseparation of (RS)-Propranolol

In this work, four cyanuric chloride based chiral reagents were prepared via nucleophile substitution of chlorine atom by L-proline derivatives and characterized by UV, FT-IR, HRMS, NMR and elemental analysis. Racemic propranolol was chosen for the chiral recognition study. The prepared chiral reagents were used in the synthesis of diastereomeric derivatives of (RS)-propranolol, under microwave heating conditions. RP-HPLC was used to separate the prepared diastereomeric derivatives. The effect of varying eluting phase concentrations and sample concentrations was optimized. The DFT calculations were performed using Gaussian 09 Rev A.02 to create the lowest energy optimised structures of diastereomeric derivatives. LOD (0.324 ng mL-1), LOQ (0.972 ng mL-1), calibration range (0.02-2.0 mg mL-1), correlation-coefficient (0.999), and recovery were the validation parameters for the present method (99.09 and 99.81 % for inter-day assay and 98.47 and 99.72 % for intra-day assay).

Validation of a New Sensitive Method for the Detection and Quantification of R and S-Epimers of Ergot Alkaloids in Canadian Spring Wheat Utilizing Deuterated Lysergic Acid Diethylamide as an Internal Standard

Ergot sclerotia effect cereal crops intended for consumption. Ergot alkaloids within ergot sclerotia are assessed to ensure contamination is below safety standards established for human and animal health. Ergot alkaloids exist in two configurations, the R and S-epimers. It is important to quantify both configurations. The objective of this study was to validate a new ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for quantification of six R and six S-epimers of ergot alkaloids in hard red spring wheat utilizing deuterated lysergic acid diethylamide (LSD-D3) as an internal standard. Validation parameters such as linearity, limit of detection (LOD), limit of quantification (LOQ), matrix effects, recovery and precision were investigated. For the 12 epimers analyzed, low LOD and LOQ values were observed, allowing for the sensitive detection of ergot epimers. Matrix effects ranged between 101–113% in a representative wheat matrix. Recovery was 68.3–119.1% with an inter-day precision of <24% relative standard deviation (RSD). The validation parameters conform with previous studies and exhibit differences between the R and S-epimers which has been rarely documented. This new sensitive method allows for the use of a new internal standard and can be incorporated and applied to research or diagnostic laboratories.

Simultaneous Determination of Ten Bioactive Components from Shenling Baizhu San in Rat Plasma by UHPLC-MS/MS: Application to a Comparative Pharmacokinetic Study in Normal and Two Models of Ulcerative Colitis Rats

Shenling Baizhu San, a traditional formula, has a long history of treating spleen asthenic diarrhea by invigorating the spleen and dispelling dampness in China. A rapid and accurate UHPLC-MS/MS method was developed and fully validated for the simultaneous determination of ten active constituents in rat plasma: panaxadiol, ginsenoside Rg1, atractylenolide I, atractylenolide III, pachymic acid, neferine, nuciferine, diosgenin, platycodin D, and isoliquiritigenin. The plasma samples were pretreated by the protein precipitation method with acetonitrile. The analytes and puerarin (internal standard) were determined with high selectivity and sensitivity (LLOQ, 0.31–0.68 ng·mL−1) within 10 minutes. The validation parameters, including intra-/interday precisions, accuracy, recovery, matrix effect, and stability, were within acceptable ranges. The validated method was successfully applied to the pharmacokinetics study of ten components in normal and two rat models of ulcerative colitis (i.e., spleen deficiency with dampness retention-ulcerative colitis (SDDR-UC) rats and pure-ulcerative colitis (P-UC) rats). The pharmacokinetic parameters were significantly different among the three groups of rats. Overall, the absorption of the components was shown as follows: normal group > SDDR-UC group > P-UC group. The study could provide a scientific basis for further studies on pharmacokinetics and clinical differential application of SDDR-UC and P-UC patients.

Laboratory diagnosis of the Tropicamide non-drug consumption

Introduction. Lately, medical services have reported a lot of cases caused by taking Tropicamide alone or with other drugs together. Moreover, it has been declared that the increase in the number of resistance cases to Tropicamide consumption has. Due to those facts, Tropicamide was included in the List of Drugs for Medical Use that should be served by the prescriptions in 2015. However, nowadays in Russia there are many combinations of medicines, for instance, Tropicamide and α-adrenergic agonist (phenylephrine) (Midrimax, Fenikamid, Appamide plus) that are not under that regulation. As a result, those medicines are served in pharmacies without any prescriptions. Thus, method developing for Tropicamide determination in the hair samples to establish his consumption period has become a perspective one.Aim. The research aimed to develop a method for the isolation and determination of Tropicamide in the hair samples.Materials and method. Reference standard of Tropicamide was used in this research. The following enzymes – papain, chymopsin, chymotrypsin, and hyaluronidase – were applied in the experiment. To design the long-term consumption of Tropicamide, laboratory animals (Guinea pigs, average masses about 200 – 250 g) with fair and brown nature colour hair were used in this research. The hair of laboratory animals was dyed by professional hair-dye "Estel Professional De Luxe". The following equipment was applied: balance "Sartorius СР224S", pH-meter " FiveEasy ", ball mill Retsch MM-200. The hair samples extracts were analyzed by gas chromatography with mass selective detection (Gas chromatograph model 7890А with mass selective detector model 5977 and MassHunter GC/MS software by Agilent Technologies).Results and discussion. All developed methods of enzymatic hydrolysis (by papain, chymopsin, chymotrypsin, and hyaluronidase) revealed comparable results for the Tropicamide determination in the hair samples. The research showed that the amount of the analyte isolated from the pigmented hair was a bit higher in comparison with the other hair samples (fair hair), despite the melanin gives chemical steadiness property to hair stuff. Moreover, the amount of Tropicamide extracted from the dyed hair samples increased by 30 %. The degradation products of the analyte of interest were not found in the extracts obtained for the dyed hair samples. Thus, the colorant does not destroy the xenobiotic during the hair dying procedure and does not impact the enzymatic hydrolysis process. The values of the validation parameters (precision and accuracy) met the required criteria for bioanalytical methods. Therefore, the enzymatic hydrolysis method can be recommended for application in laboratory practice.Conclusion. In the course of the study, a method for laboratory diagnostics of non-drug use of tropicamide was developed, the reproducibility of which meets the acceptance criteria for bioanalytical methods, which makes it possible to recommend it for work in laboratory practice.

Stability Indicating HPLC Method for Estimation of Thymoquinone in Nasal Simulated Fluid: Method Development and Validation

Introduction: A simple rapid and precise HPLC method was developed for estimation of TH in nasal simulated fluid and stability was assessed in various stressed conditions. Methods: Chromatographic separation of TH in nasal simulated fluid was done using HPLC AS-4050 coupled with Jasco UV 2075 Plus detector, Jasco LC-Net 11/ADC valve, Jasco PU-2080 pump and hypersil gold C18 (250x6x5 µm) column, ChromNAV 2.0 Chromatography Data System software with mobile phase as acetonitrile: water (65:35) and acetonitrile: NSF (60:40) at a flow rate of 1ml/min and having run time of 10 min with loop volume of 20 µl and detection wavelength of 252 nm. The method was validated for accuracy, precision, linearity, specificity, and sensitivity in accordance with ICH (Q2B) guidelines. Results: The results of all the validation parameters were found to be within the acceptable limits. The calibration plots were linear over the concentration ranges from 2 to 14µg/ml. The accuracy and precision were found to be between 97.04±0.112 to101.081±0.0191and ≤2% for three drugs. Developed method was successfully applied for the determination TH in nasal simulated fluid and recovery was found to be >98% for three drugs. The degradation products produced as a result of stress studies did not interfere with drug peak. Conclusion: The developed method was found to be simple, specific, economic, reliable, accurate, precise, and reproducible used as a quality control tool for analysis of pure thymoquinone in nasal simulated fluid.